Graham_Wright
Well-known member
Anyone know what happened to the inflatable berth cushion idea to prevent sinking after holing?
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EMERGENCY INTERNAL BUOYANCY
- Thread starter Graham_Wright
- Start date
squidge
New member
they sunk without a trace !
He He
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He He
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Talbot
Active member
simple calculation will show that they would be unable to support the weight of the boat unless they filled a large part of the internal volume of the boat, and would thus be made of such thin material that they would chafe and burst.
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mirabriani
New member
There used to be a trailer sailer ("E Boat"?) that used empty plastic containers in voids for this purpose. I believe some owners tested them too. Duck!
Others use the containers in boxes of wine. Clean them out well though, if you
have rodents on board they like to nibble tasty valves.
Regards Briani
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Others use the containers in boxes of wine. Clean them out well though, if you
have rodents on board they like to nibble tasty valves.
Regards Briani
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StugeronSteve
New member
Sure I read an article somewhere about a holed mobo being kept afloat by an inflated dinghy in the forepeak.
<hr width=100% size=1>Think I'll draw some little rabbits on my head, from a distance they might be mistaken for hairs.
<hr width=100% size=1>Think I'll draw some little rabbits on my head, from a distance they might be mistaken for hairs.
philip_stevens
Active member
The AllyDuck range of aluminium "RIBS" has all the sealed voids filled with hundreds of small poly bottles.
<A target="_blank" HREF=http://www.allyduck.co.uk/>http://www.allyduck.co.uk/</A>
<hr width=100% size=1>regards,
Philip
<A target="_blank" HREF=http://www.allyduck.co.uk/>http://www.allyduck.co.uk/</A>
<hr width=100% size=1>regards,
Philip
capt_courageous
New member
Ask Sunsail
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Graham_Wright
Well-known member
Simple the calculation ain't!
You need to take into account all the volume occupied by the contents of the boat and the hull itself and work out its weight to determine the residual bouyancy required. As a rough indication, that part of the boat which is submerged provides sufficient buoyancy to keep it afloat obviously. It might be fairly straightforward to work out the displacement from that. There used to be several companies who offered such systems;- did they all get it wrong? If not, where are they?
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You need to take into account all the volume occupied by the contents of the boat and the hull itself and work out its weight to determine the residual bouyancy required. As a rough indication, that part of the boat which is submerged provides sufficient buoyancy to keep it afloat obviously. It might be fairly straightforward to work out the displacement from that. There used to be several companies who offered such systems;- did they all get it wrong? If not, where are they?
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BrendanS
Well-known member
Do a search for two of the lengthy threads on the subject here on the forums in the past. Interesting reading
<hr width=100% size=1>Me transmitte sursum, caledoni
<hr width=100% size=1>Me transmitte sursum, caledoni
William_H
Well-known member
I think the amswer lies in sealing off areas that you can either sacrifice as not available for storage or used only for infrequently accessed storage. So a bulkhead at the foot of the quarter berths would give a huge bouyancy compartment similarly the bow area could be sealed off. How about a waterproof door at the front cabin headsCertainly under bunk areas can be sealexd.Perhaps even the under floor bilges could be sealed.
The water is either going to come in through the forward or main hatch or through a hole. Then you have the situation of rising water in the cabin. The more it sinks the more water is likely to come in so bouyancy will help slow down the ingress.
I think it is important to have the bouyancy in the chine area to help with keeping it upright and balnced between the bow and stern.
How much bouyancy? Is an interesting question I suspect not as much as you might think. You should look to at least match the balast ie keel and as much more as you can fit bearing in mind that the hull material will probably support itself ie wood or F/G regards will
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The water is either going to come in through the forward or main hatch or through a hole. Then you have the situation of rising water in the cabin. The more it sinks the more water is likely to come in so bouyancy will help slow down the ingress.
I think it is important to have the bouyancy in the chine area to help with keeping it upright and balnced between the bow and stern.
How much bouyancy? Is an interesting question I suspect not as much as you might think. You should look to at least match the balast ie keel and as much more as you can fit bearing in mind that the hull material will probably support itself ie wood or F/G regards will
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Strathglass
New member
I fitted out my Eboat with internal buoyancy using large blocks of polystyrene several years. Several others were also done.
This was as a direct result of me being in a race when another E Boat was lost (ie sunk in less than a minute) when sailing in heavy weather without washboards.
I believe that a few years later a swamping test was carried out on one fitted out in a similar manner. I was not involved with those tests.
Details of the block sizes, positions and all my calculations ware published in the class newsletter. That must have been about 15 - 20 years ago.
My boat was mainly used for racing on the Forth so I was not concerned about storage space.
It is very important that a large proportion of the buoyancy is at the ends and just under the deck. But the deck will not support the weight of the craft. So it can't just be strapped under the deck.
It is much easier to do this to the E Boat than many other boats as, although it is 22 ft long and quite beamy they only weigh a ton and the keel weighs either 650 or 700 lbs depending on the version.
At the time I did discuss what I was doing with the designer Julian Everret and he gave me a lot of advice on what to do and what not to do.
I will still have a copy of the article somewhere but as I only recently moved house it would be virtually impossible to find at this time.
Iain
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This was as a direct result of me being in a race when another E Boat was lost (ie sunk in less than a minute) when sailing in heavy weather without washboards.
I believe that a few years later a swamping test was carried out on one fitted out in a similar manner. I was not involved with those tests.
Details of the block sizes, positions and all my calculations ware published in the class newsletter. That must have been about 15 - 20 years ago.
My boat was mainly used for racing on the Forth so I was not concerned about storage space.
It is very important that a large proportion of the buoyancy is at the ends and just under the deck. But the deck will not support the weight of the craft. So it can't just be strapped under the deck.
It is much easier to do this to the E Boat than many other boats as, although it is 22 ft long and quite beamy they only weigh a ton and the keel weighs either 650 or 700 lbs depending on the version.
At the time I did discuss what I was doing with the designer Julian Everret and he gave me a lot of advice on what to do and what not to do.
I will still have a copy of the article somewhere but as I only recently moved house it would be virtually impossible to find at this time.
Iain
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